Method and machine tool for machining a tire of a train wheel set

ABSTRACT

Disclosed is a wheel set which comprises two wheel disks and is placed upon several support and drive rollers of a movable wheel set machine. The wheel set axle is the received between lathe centers of two tailstocks which are supported relative to each other. The position of the wheel set relative to the center of the machine is identified. A tool for machining the tire of at least one of the two wheel disks of the wheel set if first adjusted in the Z direction of the machine according to the result of the identification, the wheel set being made to rotate by means of one of the support and drive rollers. The back of the tire is subsequently planed with the aid of the tool. The planed back of the tire is supported in the Z direction, and the supported tire is profiled beginning from the front face thereof by means of a tool.

The invention relates to a method and a machine tool for machiningrunning surfaces of a railroad wheel set.

A machine for machining of running surfaces of a railroad wheel set bygrinding has become known e.g. through U.S. Pat. No. 2,754,630. In thismachine the wheel set is received between the back centers of twotailstocks and is imparted rotation by a friction roller while therunning surface is profiled by means of a grinding tool. Two frictionrollers are provided in particular and do not attack at thecircumference of the running surface vertically below the wheel set heldbetween the back centers but laterally thereof. Running surfaces ofrailroad wheel sets can be machined essentially only by grinding withthe known machine because considerably great cutting forces that do notallow for precise machining of the wheel set without strong support inthe machine frame occur for the machining e.g. by turning or millingthan by grinding. The machine frame of the known wheel set grindingmachine is supported on runners and is thus movable.

Furthermore a method and a machine for the machining of railroad wheelsis known from DE 100 25 724 A1 whose machine frame is also designed soas to be movable. The wheel disks or brake disks of a railroad wheel orwheel set rotatably supported in bearing housings are grasped by a chuckengaged at least at one bearing housing in that the wheel set with awheel set is pressed at the latter's circumference against supportingrollers of which at least one causes the railroad wheel or the wheel setto rotate while at the same time a tool machines one of the wheel orbrake disks. This machine is especially well suited to machine railroadwheels or wheel sets built onto the vehicle while they are beingmachined. Due to its mobility the machine can also be used economicallyto machine small-size batches.

This leads to the object of the present invention to further improve theknown methods and machines and to provide also for the machining ofrunning surfaces that were recently installed on the wheel disks ofrailroad wheel sets. The advantage of mobility should at the same timebenefit economic utilization for smaller-size batches.

According to the invention, the object is attained by two separateprocesses:

-   -   1. By placing the wheel set with both wheel disks on several        supporting and drive rollers of a mobile wheel set machine,    -   by receiving and centering the wheel set axle between the back        centers of two supported tailstocks,    -   by ascertaining the position of the wheel set relative to the        center of the machine,    -   by adjusting a tool for the machining of the running surface of        at least one of the two wheel disks of the wheel set first in Z        direction of the machine in function of the result of the        ascertainment,    -   by imparting rotation to the wheel set with at least one of the        supporting and drive rollers,    -   by then planing the back of the running surface by means of the        tool,    -   by supporting the planed back of the running surface in        direction Z and    -   by profiling the supported running surface by means of a tool.    -   2. Or by receiving and centering the wheel set axle between back        centers of two supported tailstocks of a mobile wheel set        machining machine,    -   by ascertaining the position of the wheel set relative to the        center of the machine,    -   depending on the result of the ascertainment, by adjusting a        tool for the machining of the running surface of at least one of        the two wheel disks of the wheel set,    -   by pressing a drive roller against at least one of the two wheel        disks of the wheel set and imparting rotation with it to the        wheel set,    -   by then planing the back of the running surface by means of the        tool,    -   by supporting the planed back of the running surface in        direction Z and    -   by profiling the supported running surface by means of a tool.

The term “profiling” means the chip-removing machining of the outercontour of the wheel's running surface. This machining can be carriedout by turning, milling or, as is known, by grinding.

The position of the wheel set in relation to the center of the mobilemachine is ascertained e.g. by tracing a shoulder or relief of the wheelset axle by means of a tracer. Following this, the back of one or bothrunning surfaces of the two wheel disks of the wheel set are planed,each by means of a tool. During this planing the AR distance between thetwo backs of the running surfaces is at the same time adjusted. The “ARdistance” is the distance between the two wheel disks. The AR distanceis measured from wheel back to wheel back of the two running surfaces ofa wheel set. In addition to the AR distance, the QR distance is alsosignificant. The QR distance is the wheel gauge between rubbing faces ofinner wheel flanges as measured at the point of transition from runningsurface to wheel flange.

When the backs of the two running surfaces have been planed and when theAR distance has been reached, the wheel disk is supported in Z directionby means of a roller for the profiling of the running surfaces.Supporting the wheel disks ensures that the wheel disk does not warp insuch manner during the subsequent profile machining as to cause lack ofprecision in the production result. As soon as the AR distance or the QRdistance has been adjusted, a program takes over the control of the toolcarriages for the profiling of the running surfaces.

Brake disks that may also be present on the wheel set are also machinedby means of a tool. It may be advantageous to use the same tool for themachining of the running surfaces and of the brake disks.

A machine tool for machining of running surfaces and/or brake disks ofrailroad wheel sets by chip-removing machining is characterized by

-   -   a movable machine frame,    -   two back centers capable of being displaced along a tailstock,        at a distance from each other in Z direction of the machine        frame equal to the length of the wheel set axle and aligned with        each other,    -   a common support of the two tailstocks,    -   at least one supporting and/or drive roller suitable to be        pressed against the running surface of at least one of the two        wheel disks of the wheel set,    -   at least one installation for the ascertainment of the position        of the wheel set in Z direction relative to the center of the        machine frame,    -   at least one tool carriage with at least one tool,    -   a forward feed to move the tool carriage at lest in X and Z        direction and    -   a support of the running surface to be re-profiled, in Z        direction.

The common support of the two tailstocks can consist of a yoke on eachtailstock and of two tow bars connecting the two yokes to each other,extending along the machine frame on either side of the wheel set heldbetween the back centers.

It is advantageous if two supporting and drive rollers are provided foreach wheel disk of the wheel set. As a result the torque transmitted persupporting and drive roller can be kept low, so that no slippage occursbetween the drive and the running surface. For this arrangement the twosupporting and drive rollers are installed at a distance from each othernearly vertically below the wheel set held between the back centers.Such an installation makes it also possible to place the wheel set onthe supporting and drive rollers before it can be held between the backcenters. This arrangement is especially advantageous for theimplementation of the method according to claim 1.

When setting a wheel set on the two supporting and drive rollers it isadvantageous if the supporting and drive rollers can be moved indirection X. In this manner the wheel set placed on the rollers can belifted to a level at which the wheel set axle can be received betweenthe back centers.

To ascertain the position of the wheel set relative to the machineframe, a tracer is provided that can be displaced at least in Z and Xdirection. In addition to the mobility in X and Z direction it is alsoadvantageous if the tool support can also be displaced in direction Y.As a result the possibilities increase for the placement of the toolholder for tools and tracers. In this sense the tool carriage is alsoequipped with a tool holder which makes either the holding of machiningtools for the running surfaces and/or the brake disks or a tracer.

Finally a supporting roller is provided which is born rotatably and canbe displaced along direction Z, being capable of absorbing forces actingin Z direction. By means of this supporting roller the wheel disk issupported during profiling of the running surface on the latter's outercircumference, so that the wheel disk does not warp under the stress ofchip removal.

The invention is described in further detail below through an example ofan embodiment.

At reduced scale

FIG. 1 shows a machine tool in a front view

FIG. 2 shows the support of a tailstock in a top view

FIG. 3 shows a tool carriage in a front view

FIG. 4 shows an enlarged detail “A” from FIG. 3 and

FIG. 5 shows an enlarged detail “B” from FIG. 1.

On the side next to FIG. 1 the main work or feed devices of the turningmachine are shown in perspective. These are the Z directioncorresponding to axis of rotation 24 of the wheel set axle 7, Xdirection corresponding to the perpendicular to the machine frame 5 andY direction corresponding to a perpendicular to the plane of the drawingof FIG. 1.

The machine tool for the machining of running surfaces 1 and/or brakedisks 18 of railroad wheel sets 2 is provided with a movable machineframe 5. The mobility of the machine frame 5 is made possible e.g. byrollers 6 running on rails 23. Two back centers 8 are supported in atailstock 9 and are capable of being displaced and rotated. The backcenters 8 are at a distance from each other in Z direction of themachine frame 5 that is equal to the length of the wheel set axle 7. Thetwo tailstocks 9 are supported mutually, each via a yoke 20 and two drawbars 21 (FIG. 2).

Two supporting and drive rollers 4 are provided for each wheel disk 3 ofthe wheel set 2. The two supporting and drive rollers 4 are at adistance from each other in Y direction and are nearly vertically belowthe wheel set 2 held between the back centers. In addition the twosupporting and drive rollers 4 can be adjusted and fixed in X direction.Thus the wheel set to be machined can be placed first on the supportingand drive rollers 4 and can be lifted by these to a level at which itsaxis of rotation 24 is aligned with the two back centers 8.

Before starting machining, the precise position of the wheel set 2relative to the longitudinal center 10 of the movable machine frame 5 isascertained. For this purpose a tracer 16 is brought into contact with ashoulder 15 or relief, whereby it is assumed that the wheel set axle 7has already undergone a preparation in the course of which the two wheeldisks 3 have been brought into the planned position on the wheel setaxle 7. The tracer 16 is seated in a tool receptacle 22 which is part ofthe carriage 19. Upon ascertaining the position of the wheel set 2relative to the longitudinal center 10 of the machine frame 5, thetracer 16 is taken out of the tool receptacle 22 and in its steadcutting tools 11 and 14 are inserted into the tool receptacle 22. Bydisplacing the carriage 19 in Z and X direction during simultaneousrotation of the wheel set 2, the back 12 of the running surface 1 canfirst be planed. The two backs 12 of the two running surfaces 1 areplaned first and at the same time the AR distance 13 is adjusted. Afterthe planing of the two running surface backs 12 the cutting tool 1 isagain disengaged and is applied to the front 25 of the running surfaceby a movement of the carriage 19 in Z and X direction. Finally therunning surface 1 is profiled as shown in FIGS. 1, 2 and 3 by means ofthe cutting tool 14 while the tool carriage 19 moves in accordance witha control program by means of the built-in advance feed (not shown).During this profiling the wheel disk 3 is supported on the back 12 ofthe running surface 1 by a roller 17 in Z direction. The roller 17rotates together with the rotating wheel set 2.

In addition to the profiling of the running surfaces 1, it is alsopossible to plane the brake disks 18 by means of the cutting tools 11 or4 or by means of special tools inserted into the tool receptacle 22. Ascan be seen in the figures, the two brake disks 18 are seated on thewheel set axle 7 within the AR distance 13.

1. Method for machining running surfaces of a railroad wheel set,wherein the wheel set with both wheel disks is placed on severalsupporting and drive rollers of a movable wheel set machine, the wheelset axle is received and centered between back centers of two supportedtailstocks, the position of the wheel set relative to the center of themachine is ascertained, depending on the result of the ascertainment, atool is first is adjusted first in Z direction of the machine to machinethe running surface of at least one of the two wheel disks of the wheelset, the wheel set is imparted rotation by at least one of thesupporting and drive rollers, the back of the running surface is thenplaned by means of the tool, the planed back of the running surface issupported in Z direction and the supported running surface is profiledby means of a tool.
 2. Method to machine running surfaces of a railroadwheel set, wherein the wheel set axle is received and centered betweenback centers of two supported tailstocks of a movable wheel setmachining machine, the position of the wheel set relative to the centerof the machine is ascertained, depending on the result of theascertainment, a tool for the machining of the running surface of atleast one of the two wheel disks of the wheel set is first adjusted in Zdirection of the machine, a drive roller is applied to the runningsurface of at least one of the two wheel disks of the wheel set androtation is thereby imparted to the wheel set, the back of the runningsurface is then planed by means of the tool, the planed back of therunning surface is supported in Z direction and the supported runningsurface is profiled by means of a tool.
 3. Method as in claim 1, whereinthe running surfaces are planed and/or profiled by turning, milling orgrinding.
 4. Method as in claim 1, wherein the position of the wheel setrelative to the center of the machine is ascertained by tracing ashoulder or relief of the wheel set axle by means of a tracer.
 5. Methodas in claim 1, wherein the backs of each of the running surfaces of thetwo wheel disks of the wheel set are planed by means of a tool. 6.Method as in claim 5, wherein the AR distance between the two backs ofthe running surfaces is adjusted.
 7. Method as in claim 1, wherein theplaned back of the running surfaces is supported in Z direction by meansof a roller.
 8. Method as in claim 1, wherein brake disks that may alsobe present on the wheel set are machined by means of a tool.
 9. Methodas in claim 8, wherein the same tool is used to machine brake disks asto machine running surfaces.
 10. Machine tool for the machining ofrunning surfaces and/or brake disks of railroad wheel sets bychip-removing machining, wherein a movable machine frame, two backcenters each of which is supported in a tailstock so as to bew capableof longitudinal displacement and rotation and at a distance from eachother in Z direction of the machine frame equal to the length of thewheel set length and aligned with each other, a common support of thetwo tailstocks at least one supporting and/or drive roller that can bebrought to bear against the running surface of at least one of the twowheel disks of the wheel set (2) which can be brought into contact with.at least one apparatus to ascertain the position of a wheel set in Zdirection relative to the center of the machine frame, at least one toolcarriage with at least one tool one advance feed to move the toolcarriage at least in directions X and Z and one support of the runningsurfaces in Z direction.
 11. Machine tool as in claim 10, wherein thecommon support of the two tailstocks consist of a yoke for eachtailstock and two draw bars connecting the two yokes with each other.12. Machine tool as in claim 10, wherein two supporting and driverollers are provided for each wheel disk of the wheel set.
 13. Machinetool as in claim 12, wherein the two supporting and drive rollers are ata distance from each other and are located nearly vertically below thewheel set held between the back centers.
 14. Machine tool as in claim13, wherein the two supporting and drive rollers can be adjusted andfixed in X direction.
 15. Machine tool as in claim 10, wherein a tracermovable at least in Z and X directions is provided.
 16. Machine tool asin claim 10, wherein the tool support is movable in X, Y and Zdirections.
 17. Machine tool as in claim 15, wherein the tool carriageis provided with a tool receptacle to receive a machining tool or atracer
 18. Machine tool as in claim 10, wherein at least one rotatablymounted supporting roller is provided and is longitudinally movable in Zdirection.